Shock absorber



J- F. WALLACE SHOCK ABSORBER April 27, 1948.

Filed Feb. 2, 1945 2 Sheets-Sheet 1 3 INVENTOR.

JOHN F. WALLACE- BY r M, M, 4

ATTORNEYS April 27; 1948.

' 'J. F. WALLACE 2,440,353

SHOCK ABSORBER Filed Feb. 2, 1945 2 Sheets-Sheet 2 INVENTOR. JOHN F.WALLACE ATTORNEYS drical elements l and l Patented Apr. 27, 1948 SHOCKABSORBER John F. Wallace,

University Heights, Ohio, asslgnor to The Cleveland Pneumatic l Too Gopany, Cleveland, Ohio, a corporation of Ohio Application February 2,1945, Serial No. 575,858

2 Claims.

' This invention relates to improvements in shock absorbers, moreparticularly hydropneumatlc shock absorbers for airplanes. Shockabsorbers for this purpose are often of the type in which a metering pinborne by one of two telescoping elements is aligned with an orificecarried by the other element, and runs through that orifice in theoperation of the strut. The orifice plate is usually mounted in theinner end of. a tube which is attached at its outer end to the secondtelescoping element and which surrounds the metering pin when the shockabsorber is compressed. It is important to center this tube accurately,especially the free end thereof in which the orifice plate is situated.Heretofore this has been an expensive part of the assembly, partlybecause the position of the attaching means is such as to be hard to seeand to reach.

One of the objects of thepresent invention is the provision of a methodand means for mounting the aforesaid tube which shall lend itself torapid assembly and require little skill.

Another object is the provision of means which shall utilize the ressurefluid in the strut for perfooting the centering of the orifice plate andthat of the metering pin automatically.

Other objects and features of novelty will appear as I proceed with thedescription of those embodiments of the invention which, forthe purposesof the present application, I have illustrated in the accompanyingdrawings, in which Fig. l is an elevational view, partly in verticalsection, of a hydropneumatic shock absorber for airplanes embodying theinvention.

Fig. 2 is an enlarged fragmental detail sectional view of the orificeplate and associated parts.

Fig. 3 is a horizontal sectional view on a larger scale. takensubstantially on the line 3--3 of Fig. 1.

Fig. 4 is a fragmental view similar to a portion of Fig. 1 but showingthe shock absorber in the process of being assembled.

Fig. 5 is a fragment-a1 view similar to Fig. 4

illustrating a modified form of the invention.

Fig. 6 is a iragmental vertical sectional view of a modified form of theinvention.

Fig. 7 is a fragmental vertical sectional view on a larger scaleillustrating the mounting of the metering pin which provides automaticcentering of the latter.

Fig. 8 is a view similar to Fig. 6 showing a modified form of mountingfor the metering pin and for the orifice plate, and

Fig. 9 is a horizontal sectional view on a larger scale takensubstantially on the line 9--9 of Fig. 8.

Referring first to Figs. 1, 2 and 3 of the drawings, I have thereillustrated a hydropneumatic shock absorber comprising two telescopingcylin- I. On the inner end of element ii there is mounted a sleeve orring l2 which has a nice sliding fit upon the inner wall v dius.

I0 and H,

of element 10. The element I0 is shown closed at its outer end by anintegral end wall l3, while the element H is closed preferably by aseparate end wall It threaded into that element. these features of theconstruction being unimportant so far as the present invention isconcerned.

Element ll carries a metering pin l5 of more or less conventional formhaving a base It which fits somewhat loosely into a socket ll for apurpose which will later appear. The I5 extends through an orifice I8 inan orifice plate I! mounted in a socket 20 formed in a carrier 2| which,in the illustrated case, is a piston slidable in the element H. A pistonring 22 serves to seal the sliding joint between this piston and itscylinder. In order to prevent accidental dislocation of the orificeplate I9, I may mount a split ring 23 in fitting it into a groove in thecarrier which is so located that the plate l9 has some freedom ofmovement lengthwise of the strut, this clearance being exaggerated inFig. 2 of the drawing in order to better illustrate the invention. Thesocket 20 is also of slightly greater diameter than the diameter ofplate l9.

Cylindrical element ll. slightly below the ring or sleeve l2, may have apair of oppositely disposed ports 24 therethrough which at times providecommunication from one side to the other of the element H, but which maybe covered by spring leaf valves 25 disposed between ring l2 and a rib23 on element I I. At the lower end of cylindrical element Ill there isan internal packing 21 which may be of any conventional character andmay be held in place by a gland nut 28 threaded into the element andconstituting a bearing between the two telescoping elements.

The piston or carrier 2| is supported by a tube 29 which extendsupwardly to the end wall I3 of element iii. In that wall there is formeda spherical cavity 30 which is centered with respect to the element axisas nearly as may be. In the end wall I3 I also drill an axial hole 3iand thread the .same for the reception of a stud 32. The upper extremityof tube 29 is closed by an end wall 33 also of spherical contour, thesetwo curved surfaces being formed upon the same ra- Wall 33 has a centralbore 34 somewhat larger than the diameter of stud 32. A washer 35 havinga spherical surface complementary to the inner surface of wall 33surrounds in 32, and a nut 36 is threaded onto the stud beneath thewasher 35. v

In assembling this part of the device prior to bringing together the twotelescoping elements the tube 29 and the carrier 2| are pushed intoplace in the cylinder III, the opening 34 in the end wall of the tubebeing caused to surroundthe stud 32 so that the convex upper I againstthe concave surface end of the tube seats 30 of the element in themanner of a ball and metering pin the carrier 2 I, that is by

